The differential scanning calorimeter is an apparatus in which the sample and the reference material (which is a thermally stable reference material, and aluminum or the like is ordinarily used) are symmetrically disposed, and a heat flow that the sample excessively generates or absorbs in comparison with the reference material when temperatures of both are changed at a constant velocity is differentially detected and analyzed.
In a case where the temperature of the sample is raised at the constant velocity, a heat absorption by the sample increases as a heat capacity of the sample becomes large. That is, an absolute value of a differential heat flow signal becomes large. At this time, from the fact that the absolute value of the differential heat flow signal is proportional to a heat capacity difference between the sample and the reference material, and a temperature raising velocity, it is possible to know the heat capacity of the sample from the differential heat flow signal on the basis of the temperature raising velocity and a reference heat capacity, which are already known.
On the other hand, when the sample melts, a heat absorption by the sample becomes temporarily large and, if the differential heat flow signal recorded in time series is made a graph, the differential heat flow signal depicts an endothermic peak. Further, according to a similar recording method, if a crystallization occurs in the sample, the differential heat flow signal depicts an exothermic peak. Since areas of these endothermic and exothermic peaks depicted in regard to a time axis set such that a unit time corresponds to a constant length are proportional to a heat quantity (transition heat) that the sample discharges or absorbs when it transfers, if a known transition heat is previously measured and a signal value is calibrated, it is possible to easily find the transition heat of the sample from the differential heat flow signal. In order to obtain the differential heat flow signal having a useful nature like the above, the differential scanning calorimeter is widely used in analyses of various materials.
Hitherto, as the differential scanning calorimeter of this kind, there are ones shown in FIG. 5, FIG. 6 and FIG. 7.
FIG. 5 is one disclosed in JP-A-2003-42985 Gazette, in which a heat flows from a convex protrusion part 1 a provided in a bottom part center of a heat reservoir to a sample side holder 3 and a reference side holder 4 through a long-plate-like heat flow passage 2 made of a metal material, and a temperature difference is detected by thermocouples installed in back faces of the respective holders. Additionally, in this example, for the purpose of raising a heat flow responsiveness (heat compensation time constant is decreased), a heater for compensating an input is provided in a holder part, thereby making a constitution of an input compensation type DSC.
FIG. 6 is disclosed in JP-UM-A-60-64250 Gazette, and a form is provided in which a detector is directly mounted on a bottom plate of a heating furnace comprising a good heat conductor, whose section is like an H-letter, a temperature distribution is suppressed by providing a neck-like part in a heat flow passage in the detector, and a heat one-dimensionally flows into a sample part and a reference part.
FIG. 7 is one disclosed in JP-A-2000-28559 Gazette, and a structure is provided in which, in order to improve the heat flow responsiveness, a sensor, in which a heat flow passage 3 is two-dimensionally disposed, is installed on a heat reservoir bottom plate through a heat buffer plate 6 formed by a low thermal conduction material.